Abstract
Caveolin-3, a muscle-specific caveolin-related protein, is the principal structural protein of caveolae membrane domains in striated muscle cell types (cardiac and skeletal). Autosomal dominant limb girdle muscular dystrophy (LGMD-1C) in humans is due to mutations within the caveolin-3 gene: (i) a 9- base pair microdeletion that removes three amino acids within the caveolin scaffolding domain (ΔTFT) or (ii) a missense mutation within the membrane spanning domain (P → L). The molecular mechanisms by which these two mutations cause muscular dystrophy remain unknown. Here, we investigate the phenotypic behavior of these caveolin-3 mutations using heterologous expression. Wild type caveolin-3 or caveolin-3 mutants were transiently expressed in NIH 3T3 cells. LGMD-1C mutants of caveolin-3 (ATFT or P → L) were primarily retained at the level of a perinuclear compartment that we identified as the Golgi complex in double-labeling experiments, while wild type caveolin-3 was efficiently targeted to the plasma membrane. In accordance with these observations, caveolin-3 mutants formed oligomers of a much larger size than wild type caveolin-3 and were excluded from caveolae- enriched membrane fractions as seen by sucrose density gradient centrifugation. In addition, these caveolin-3 mutants were expressed at significantly lower levels and had a dramatically shortened half-life of ~45-60 min. However, caveolin-3 mutants were palmitoylated to the same extent as wild type caveolin-3, indicating that targeting to the plasma membrane is not required for palmitoylation of caveolin-3. In conclusion, we show that LGMD-1C mutations lead to formation of unstable high molecular mass aggregates of caveolin-3 that are retained within the Golgi complex and are not targeted to the plasma membrane. Consistent with its autosomal dominant form of genetic transmission, we demonstrate that LGMD-1C mutants of caveolin-3 behave in a dominant-negative fashion, causing the retention of wild type caveolin-3 at the level of the Golgi. These data provide a molecular explanation for why caveolin-3 levels are down-regulated in patients with this form of limb girdle muscular dystrophy (LGMD-1C).
| Original language | English |
|---|---|
| Pages (from-to) | 25632-25341 |
| Number of pages | 292 |
| Journal | Journal of Biological Chemistry |
| Volume | 274 |
| Issue number | 36 |
| DOIs | |
| Publication status | Published - Sep 3 1999 |
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ASJC Scopus subject areas
- Biochemistry
Cite this
Phenotypic behavior of caveolin-3 mutations that cause autosomal dominant limb girdle muscular dystrophy (LGMD-1C). Retention of LGMD-1C caveolin-3 mutants within the Golgi complex. / Galbiati, Ferruccio; Volonté, Daniela; Minetti, Carlo; Chu, Jeffrey B.; Lisanti, Michael P.
In: Journal of Biological Chemistry, Vol. 274, No. 36, 03.09.1999, p. 25632-25341.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Phenotypic behavior of caveolin-3 mutations that cause autosomal dominant limb girdle muscular dystrophy (LGMD-1C). Retention of LGMD-1C caveolin-3 mutants within the Golgi complex
AU - Galbiati, Ferruccio
AU - Volonté, Daniela
AU - Minetti, Carlo
AU - Chu, Jeffrey B.
AU - Lisanti, Michael P.
PY - 1999/9/3
Y1 - 1999/9/3
N2 - Caveolin-3, a muscle-specific caveolin-related protein, is the principal structural protein of caveolae membrane domains in striated muscle cell types (cardiac and skeletal). Autosomal dominant limb girdle muscular dystrophy (LGMD-1C) in humans is due to mutations within the caveolin-3 gene: (i) a 9- base pair microdeletion that removes three amino acids within the caveolin scaffolding domain (ΔTFT) or (ii) a missense mutation within the membrane spanning domain (P → L). The molecular mechanisms by which these two mutations cause muscular dystrophy remain unknown. Here, we investigate the phenotypic behavior of these caveolin-3 mutations using heterologous expression. Wild type caveolin-3 or caveolin-3 mutants were transiently expressed in NIH 3T3 cells. LGMD-1C mutants of caveolin-3 (ATFT or P → L) were primarily retained at the level of a perinuclear compartment that we identified as the Golgi complex in double-labeling experiments, while wild type caveolin-3 was efficiently targeted to the plasma membrane. In accordance with these observations, caveolin-3 mutants formed oligomers of a much larger size than wild type caveolin-3 and were excluded from caveolae- enriched membrane fractions as seen by sucrose density gradient centrifugation. In addition, these caveolin-3 mutants were expressed at significantly lower levels and had a dramatically shortened half-life of ~45-60 min. However, caveolin-3 mutants were palmitoylated to the same extent as wild type caveolin-3, indicating that targeting to the plasma membrane is not required for palmitoylation of caveolin-3. In conclusion, we show that LGMD-1C mutations lead to formation of unstable high molecular mass aggregates of caveolin-3 that are retained within the Golgi complex and are not targeted to the plasma membrane. Consistent with its autosomal dominant form of genetic transmission, we demonstrate that LGMD-1C mutants of caveolin-3 behave in a dominant-negative fashion, causing the retention of wild type caveolin-3 at the level of the Golgi. These data provide a molecular explanation for why caveolin-3 levels are down-regulated in patients with this form of limb girdle muscular dystrophy (LGMD-1C).
AB - Caveolin-3, a muscle-specific caveolin-related protein, is the principal structural protein of caveolae membrane domains in striated muscle cell types (cardiac and skeletal). Autosomal dominant limb girdle muscular dystrophy (LGMD-1C) in humans is due to mutations within the caveolin-3 gene: (i) a 9- base pair microdeletion that removes three amino acids within the caveolin scaffolding domain (ΔTFT) or (ii) a missense mutation within the membrane spanning domain (P → L). The molecular mechanisms by which these two mutations cause muscular dystrophy remain unknown. Here, we investigate the phenotypic behavior of these caveolin-3 mutations using heterologous expression. Wild type caveolin-3 or caveolin-3 mutants were transiently expressed in NIH 3T3 cells. LGMD-1C mutants of caveolin-3 (ATFT or P → L) were primarily retained at the level of a perinuclear compartment that we identified as the Golgi complex in double-labeling experiments, while wild type caveolin-3 was efficiently targeted to the plasma membrane. In accordance with these observations, caveolin-3 mutants formed oligomers of a much larger size than wild type caveolin-3 and were excluded from caveolae- enriched membrane fractions as seen by sucrose density gradient centrifugation. In addition, these caveolin-3 mutants were expressed at significantly lower levels and had a dramatically shortened half-life of ~45-60 min. However, caveolin-3 mutants were palmitoylated to the same extent as wild type caveolin-3, indicating that targeting to the plasma membrane is not required for palmitoylation of caveolin-3. In conclusion, we show that LGMD-1C mutations lead to formation of unstable high molecular mass aggregates of caveolin-3 that are retained within the Golgi complex and are not targeted to the plasma membrane. Consistent with its autosomal dominant form of genetic transmission, we demonstrate that LGMD-1C mutants of caveolin-3 behave in a dominant-negative fashion, causing the retention of wild type caveolin-3 at the level of the Golgi. These data provide a molecular explanation for why caveolin-3 levels are down-regulated in patients with this form of limb girdle muscular dystrophy (LGMD-1C).
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U2 - 10.1074/jbc.274.36.25632
DO - 10.1074/jbc.274.36.25632
M3 - Article
C2 - 10464299
AN - SCOPUS:0033520482
VL - 274
SP - 25632
EP - 25341
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 36
ER -